Many people like to use commands for competition that are distinctly different from the commands that they use around the house. This is one way to indicate to the dog that you are "working" and makes it easier for you as a trainer to be consistent with the behaviour that you ask for from the dog. This allows you to tell the dog to "down" around the house, and "platz" on the field, and the dog understand that "down" means "lay down" and "platz" means "lay down but continue to watch me for my next command".
In addition, using German commands honors the heritage and tradition of the German Shepherd Dog and the sport of schutzhund. And, the German language seems to lend itself to being yelled on an open field. ;-) Of course, it’s not necessary to learn to speak German, just a handful of terms. Even if you don’t choose to use them, you will probably hear them in conversation.
||Fooss (long o sound as in moose) Frequently gets conjugated as if it were an english verb, as in "Did you see him fussing with his dog?"
||Siitz (rhymes with "fits")
||Platz (rhymes with "cats")
|Here (or Front, or Come)
||hee er Hang on the "eh" sound slightly longer than usual, and roll the r (if you can).
|Fetch, Bring, Get it
||Brrring. Roll the "r"
|Search, Seek, Track
||Tsuuk, soo, The final k sound is almost silent.
|Out, Drop it, Let go
||Owss, rhymes with "house"
|Jump, Up, Over
||For owss (rhymes with "for house")
|Hunt, search the blind
||For awn. Some people use "voran" as the command to the dog to run to the blind and search it for the helper, others use "revier".
What is Pfui?
Pfui, phooey, (pronounced foo-ee) translates to "shame" as in "shame on you, you know better." It is used to tell a dog that his behaviour is not acceptable at this time - as opposed to "No" which means the behaviour is never acceptable. For instance, if you wanted to tell the dog to stop barking at someone, without telling him to never bark at anyone.
What about "Stay?"
Schutzhund considers "sit-stay" and "down-stay" to be a double command, which is not permitted in a trial. In addition, it is redundant.
For more commands, phrases, and other languages.
http://www.uwsp.edu/psych/dog/languag1.htm prounounciation sound files
http://www.eastgermanshepherd.com/german.html translation of german frequently found on pedigrees